Juanita Walker stood just steps from where her son was killed two days earlier and addressed a crowd of at least 100 people, sobbing and yelling to be heard.

"Y'all young people, you think because you're young that it might not be your time," she told the crowd at a candlelight vigil Sunday for Andre Witherspoon, 27. She said she spoke to her son 20 minutes before he was shot, just after 1 p.m. Friday in the 900 block of Ducatel St. in the Reservoir Hill neighborhood.

"We all get caught up. The environment told him, tricked him, made him believe that he had to go this way," she said. "My heart is heavy because I know he got four kids."

At least 20 people were shot in 12 incidents across the city from Friday afternoon through early Monday morning. Eight of those people — two women and six men — were killed.

Two others, a man and a woman shot in West Baltimore late Sunday night in an incident being investigated by homicide detectives, were in critical condition Monday morning.

The shootings included one in the early hours of Saturday, when at least one assailant sprayed bullets into a crowd of people in the 700 block of N. Kenwood Ave. in the city's Madison-Eastend neighborhood, wounding three women and a man and killing Donyae Jones, 18.

Besides Jones and Witherspoon, police said Danquel Darden, 37, was shot in the face and killed in a home in the 500 block of East 26th St. about 9:15 p.m. Saturday. Police have not determined a motive in his shooting.

Fatal victims also identified Monday included:

Omar Shorter, 32, killed in the 5200 block of Cuthbert Ave.; Gervontae Burgess, 20, and Joyce Alston, 49, both killed in the 1400 block of Pennsylvania Ave.; Claude Nelson, 53, killed in the 5200 block of St. Charles Ave.; and Maurice Taylor, 37, who was fatally shot in the 900 block of Bennett Place.

Anthony Guglielmi, a police spokesman, said the department added more patrols to the neighborhoods where the shootings took place and has put more plainclothes officers in known "hot spots." Homicide detectives are working to see whether any of the shootings are related to one another, perhaps in retaliation, he said.

"This is a little bit of a spike in terms of the weekend, but all in all, we're pretty satisfied with the way the city is headed, violence-wise," Guglielmi said. Several categories of crime are down this year while the numbers of homicides and shootings are similar to those at this time last year, he said.

He said the department has focused on adding as many foot patrols as possible — for example, sending out members of the sex offense unit to patrol the Central District on Saturday night.

"These incidents are going to happen, so we want to set realistic expectations," Guglielmi said. "What's important is how we respond."

Police Commissioner Anthony W. Batts could not be reached for comment Sunday. A spokesman for Mayor Stephanie Rawlings-Blake did not respond to multiple requests for comment Sunday on the shootings.

On Monday, the mayor released a statement saying police are aggressively investigating the shootings and have beefed up patrols.

"This weekend's senseless violence will not diminish our resolve to target repeat violent offenders, gangs and illegal guns," she said. "We will do everything we can to reduce gun violence and make our neighborhoods safer. But more work remains to disrupt the flow of illegal guns into America's cities."

Baltimore shootings and homicides remain near the same level as last year, with 100 people killed as of June 15 and 163 shot, according to police statistics. But the weekend violence pushed the number of homicides to 109 this year, compared with 100 people killed at the same time last year.

City Councilman Brandon Scott, the vice chair of the public safety committee, said a violent weekend such as this one was "a call for everyone to get involved" in improving the safety of the community, whether it be calling 911 to report a suspicious person or mentoring at-risk youth.

Scott, who grew up in the Park Heights neighborhood in the 1990s, which was then extremely violent, said many of the city's problems stem from deficiencies with family structure and involvement. He also said he planned to inquire about the department's deployment and response to the shootings.

"We need to talk about spending more on family-strengthening programs," he said. Scott said he and one of his childhood friends, now a firefighter, were successful, while other childhood friends have lost their way. "The only difference between us two and them is we had a family that cared about us," he said.

At the vigil for Witherspoon on Sunday, some women sobbed while men wearing shirts bearing "R.I.P. Spoon" and "Whitelock" cried more quietly. At one point, a woman began to sing a hymn, while Witherspoon's mother joined in. Witherspoon had been pronounced dead at the scene Friday, and loved ones marked the spot on the street where he was shot, still bloodstained, with lit candles. A few in the crowd released heart-shaped balloons saying "I love you" into the sky.

Witherspoon's criminal record includes convictions for robbery and selling and possessing drugs, court records show.

"It's time for the madness to stop," said Edward Walker, Witherspoon's uncle. "Peace don't cost you nothing, respect don't cost you nothing. In this day and age, it's gone."

The weekend's shootings also included, according to police:

About 7:30 p.m. Friday, a man was shot in the hand in the 1600 block of Smallwood St., in the Easterwood neighborhood in West Baltimore, and he is expected to survive.

A man died in the Arlington neighborhood after suffering multiple gunshot wounds. Officers went to the 5200 block of Cuthbert Ave. at 11:30 a.m. Saturday and found the victim, who was pronounced dead at the scene, police said. His name had not been released by Sunday night.

A man was shot about 4:20 p.m. Saturday in the Perkins Homes housing project near Fells Point, though the address police gave for the incident apparently does not exist. The man walked to the 200 block of South Broadway, where he was found with a gunshot wound to his left leg, police said. No motive has been established for that shooting, according to Detective Angela Carter-Watson, a police spokeswoman.

A man and a woman were fatally shot shortly before midnight Saturday in the 1400 block of Pennsylvania Ave. Police found them outside, suffering from gunshot wounds, and they were pronounced dead at hospitals. Police have not determined a motive, according to Carter-Watson. She said police were investigating a possible relationship between the victims. Their names had not been released by Sunday night.

A man was shot in the 5200 block of St. Charles Ave. about 4:45 a.m. Sunday, and was pronounced dead at the scene. Police have not determined a motive, according Carter-Watson. His name was not released Sunday.

Three men were injured about 1:30 a.m. Sunday when someone fired into a group of people in the 5100 block of Arbutus Ave., according to Carter-Watson. She said the three, each suffering from at least one gunshot wound, were taken to a hospital, where they were stable Sunday morning.

July has seen more than 40 homicides so far, making it the second month in 2015 that homicides in Baltimore city have risen above 40. Homicides are also up across the board since 2014. See our homicide map here for a deeper dive into the data. Data accurate as of July 29, 2015 Months with more...

In 2015, Baltimore has seen two months with more than 40 homicides in a single-year period since the 1970s when the city's population was around 300,000 more residents, or during the 1990s when the number of homicides peaked at 353 murders.

May has seen 42 homicides so far, making it Baltimore's deadliest month since 1972. Shootings this month have more than doubled compared to May 2014. Meanwhile, arrests have plummeted since April's unrest in Baltimore, with only 1,177 people arrested so far in May compared to 3,801 in the same...